## About us

Iyer research group is interested in understanding non-equilibrium complex systems, such as turbulent flows and transport of active and passive substances by such systems. A paradigm of such systems are clouds in the atmosphere. Understanding of physical interactions in a turbulent cloud is vital to the prediction of weather and climate. Ongoing projects are focused on unraveling the cloud-climate puzzle by studying the physical interactions and evolution of aerosols and cloud droplets using direct numerical simulations. Our work intersects statistical mechanics, nonlinear science and supercomputing.

## News

# Group

## Principal Investigator

#### Kartik P. Iyer

I am an Assistant Professor at Michigan Technological University with appointments in the Department of Physics and the Department of Mechanical Engineering-Engineering Mechanics. I hold affiliations in the Atmospheric Sciences Program and the Center for Applied Mathematics and Statistics at Michigan Tech. I received my PhD in Aeronautics from Georgia Institute of Technology and held postdoctoral appointments at University of Rome and New York University.

## Graduate students

### Ashvin Vinodh

I obtained my Bachelor’s in Manufacturing Engineering from Birla Institute of Technology and Science, Pilani, India, and then obtained my masters in Mechanical Engineering at the Johns Hopkins University. My primary interests lie at the intersection of physics, engineering, applied mathematics and fluid mechanics. For my PhD, I will be working on Rayleigh-Bénard Convection and how it influences clouds. Academics aside, I enjoy long walks and trails, some amount of competitive coding, and a lot of writing prompts. I have a modest reading appetite, and reading includes philosophy, dystopian fiction, economics, sci-fi and history.

## Undergraduate students

### Marc Fritts

I’m an undergraduate physics major at Michigan Technological University. I am interested in computational physics and turbulence, and would like to pursue physics graduate school in a related field! Besides problem solving and programming my hobbies include various activities like basketball, hiking, or playing card games.

# Research

Current research topics include,

- To better understand the dynamics and lifetimes of clouds in the atmosphere in order to improve modeling and prediction of Earth’s climate.
- Large scale simulations of quasi two dimensional flows to better understand the energy cascade dynamics in turbulence.
- Topological aspects of active and passive scalar mixing in turbulent media.

Follow our work at

**Research Highlights**

Our work on thermal convection got published in PNAS.

Commentary on our work in turbulent thermal convection published in Proceedings of the National Academy of Sciences by Charles Doering

Large-scale visualization of coarse-grained dissipation field in homogeneous, isotropic turbulence

# Publications

- Nonlinear amplification in hydrodynamic turbulence, with K. R. Sreenivasan and P. K. Yeung, J. Fluid. Mech.,
**930**, R2 (2022) [Article]. - The area rule for circulation in three-dimensional turbulence, with S. S. Bharadwaj, K. R. Sreenivasan, Proc. Nat. Acad. Sci.
**118**, e2114679118 (2021) [Article], [arXiv]. - Oscillations Modulating Power Law Exponents in Isotropic Turbulence: Comparison of Experiments with Simulations, with G. P. Bewley, L. Biferale, K. R. Sreenivasan and P. K. Yeung, Phys. Rev. Lett.
**126**, 254501 (2021) [Article], [arXiv]. - Reply to He et al.: The dependence of heat transport law on aspect ratio is still unclear, with J. D. Scheel, J. Schumacher and K. R. Sreenivasan, Proc. Nat. Acad. Sci.,
**117,**30024-30024 (2020) [Article]. - Classical 1/3 scaling of convection holds up to Ra = 10
^{15}, with J. D. Scheel, J. Schumacher and K. R. Sreenivasan, Proc. Nat. Acad. Sci.,**117,**7594-7598 (2020) [Article]. - Scaling exponents saturate in three-dimensional isotropic turbulence, with K. R. Sreenivasan and P. K. Yeung, Phys. Rev. Fluids
**5**, 054605 (2020) [Article], [arXiv]. - Fractal iso-level sets in high-Reynolds-number scalar turbulence, with J. Schumacher, K. R. Sreenivasan and P. K. Yeung, Phys. Rev. Fluids
**5**, 044501 (2020) [Article], [arXiv]. - Circulation in High Reynolds Number Isotropic Turbulence is a Bifractal, with K. R. Sreenivasan and P. K. Yeung, Phys. Rev. X
**9**, 041006 (2019) [Article], [arXiv]. - Self-Similar Subgrid-Scale Models for Inertial Range Turbulence and Accurate Measurements of Intermittency, with L. Biferale, F. Bonaccorso and M. Buzzicotti, Phys. Rev. Lett.
**123**, 014503 (2019) [Article], [arXiv]. - Scaling of locally averaged energy dissipation and enstrophy density in isotropic turbulence, with J. Schumacher, K. R. Sreenivasan and P. K. Yeung, New J. Phys.
**21**, 033016 (2019) [Article]. - Steep Cliffs and Saturated Exponents in Three-Dimensional Scalar Turbulence, with J. Schumacher, K. R. Sreenivasan and P. K. Yeung, Phys. Rev. Lett.
**121**, 264501 (2018) [Article]. - Multiscale anisotropic fluctuations in sheared turbulence with multiple states, with F. Bonaccorso, L. Biferale and F. Toschi, Phys. Rev. Fluids
**2**, 052602(R) (2017) [Article], [arXiv]. - Reynolds number scaling of velocity increments in isotropic turbulence, with K. R. Sreenivasan and P. K. Yeung, Phys. Rev. E
**95**, 021101(R) (2017) [Article]. - Refined similarity hypothesis using three-dimensional local averages, with K. R. Sreenivasan and P. K. Yeung, Phys. Rev. E
**92**, 063024 (2015) [Article], [arXiv]. - Rotating turbulence under “precession-like” perturbation, with I. Mazzitelli, F. Bonaccorso, A. Pouquet and L. Biferale, Eur. Phys. J. E
**38,**128 (2015) [Article], [arXiv]. - Structure functions and applicability of Yaglom’s relation in passive-scalar turbulent mixing at low Schmidt numbers with uniform mean gradient, with P. K. Yeung, Phys. Fluids
**26**, 085107 (2014) [Article]. - On the communication complexity of 3D FFTs and its implications for Exascale, with Kenneth Czechowski, Casey Battaglino, Chris McClanahan, P. K. Yeung, Richard Vuduc, ICS ’12: Proc. 26th ACM Int. Conf. Supercomput., 205-214 (2012) [Article].
- On the role of vortical structures for turbulent mixing using direct numerical simulation and wavelet-based coherent vorticity extraction, with B. Kadoch, D. Donzis, M. Schneider, M. Farge and P. K. Yeung, J. Turbul.
**12**, N20 (2011) [Article].

# Teaching

Here are the courses Dr. Iyer has taught or is currently teaching:

**Methods of Theoretical Physics PH 3320 **

This course aims to extrapolate concepts such as distance, orthogonality and dimensionality from familiar Euclidean vector spaces to abstract vector spaces . Topics include certain elements of real analysis such as convergence of sequences and infinite series, complex numbers, differentiation and integration in **R**^{p} and partial differential equations. The overarching goal is to develop familiarity with mathematical tools useful for physics applications.

- Fall 2020
- Fall 2021
- https://mtu.instructure.com/courses/1369163
- Location: Fisher 129, MWF 12 – 12:50 pm (Fall 2021)
- Office hours: Tue 3-4:30 pm; Fisher 109

**Computational Fluid Dynamics MEEM 5240 **

- This class serves as an introductory level course for using computational tools for fluid flow analysis. Topics covered include finite-difference and finite-volume methods, mathematical classification and numerical stability analysis of the equations of fluid motion. Emphasis is given to gaining numerical dexterity with implicit and explicit fluid solvers and generation of computational grids for simple flow geometries.

- Spring 2021
- Spring 2022
- https://mtu.instructure.com/courses/1347853
- Location RL Smith 303

# Service

- Dr. Iyer is the co-chair of the Physics Colloqium at Michigan Tech.
- The weekly colloqium schedule can be found here.

- Dr. Iyer serves in the graduate seminar committee in the Mechanical Engineering-Engineering Mechanics Department at Michigan Tech.
- The weekly seminar information can be found here.

# Funding

- NSF Award 2133229: A Community Laboratory Facility for Exploring and Sensing of Aerosol-Cloud-Drizzle Processes: The Aerosol-Cloud-Drizzle Convection Chamber
- XSEDE Allocation Request PHY200084: Topological vorticity sheets and scalar triple correlations in turbulence

# Contact

**If you wish to get in touch, please feel free to drop a message here**.

Follow us on

**Fisher 109, ****1400 Townsend Drive ****Houghton, MI 49931**